The four-week average, a less volatile measure, fell to 361,750, also the lowest in four years. The average has fallen nearly 13 percent in the past six months.

When unemployment benefit applications drop consistently below 375,000, it usually signals that hiring is strong enough to lower the unemployment rate.

The decline coincides with the best three months of job growth in two years. On Friday, the government issues its March jobs report, which is expected to show the fourth straight month of strong hiring.